Optimod-Surround 8685 V1.0 Operating Manual - Orban

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OPERATION ORBAN MODEL 8685
Bx Compression Threshold sets the compression threshold for each band in units
of dB. We recommend making small changes around the factory settings to preserve
the internal headroom built into the processing chain. These controls will affect the
spectral balance of the processing above threshold.
You can use the Bx SPEECH COMPRESSION THRESHOLD control to set independent frequency
balances for music and speech in the 2.0 processing chain, (page 3-6). The Bx
CENTER COMPRESSION THRESHOLD control performs a similar function in the surround
processing. It is particularly useful when setting up the center channel to de-ess dialog.
The SPEECH and CENTER controls appear only in Advanced Control.
MB Gate Threshold control determines the lowest input level that will be recognized
as program by OPTIMOD 8685; lower levels are considered to be noise or
background sounds and cause the AGC or multiband compressor to gate, effectively
freezing gain to prevent noise breathing.
The multiband gate only works appropriately when the KNEE and RATIO controls of
all bands are set identically, which is typically true in broadcast applications. We recommend
turning off the multiband gate if the individual KNEE and RATIO settings
are unequal.
There are two independent gating circuits in the 8685. The first affects the AGC and
the second affects the multiband compressor. Each has its own threshold control.
The multiband silence gate causes the gain reduction in bands 2 and 3 of the multiband
compressor to move quickly to the average gain reduction occurring in those
bands when the gate first turns on. This prevents obvious midrange coloration un-
MB Attack/Release/Threshold
Full Name Advanced Name Range
MB Release Multiband Release Slow, Slow2, Med, Med2, MFast, MFast2,
Fast
--- Speech Multiband Release Slow, Slow2, Med, Med2, MFast, MFast2,
Fast [2.0 only]
--- Center Multiband Release Slow, Slow2, Med, Med2, MFast, MFast2,
Fast [surround only]
Bx THR Bx Compression Threshold –16.00 … 0.0, Off
--- Bx Speech Compression Thresh –16.00 … 0.0, Off [2.0 only]
--- Bx Center Compression Thresh –16.00 … 0.0, Off [surround only]
--- Bx Attack 4.0 … 50.0 ms, Off
--- Bx Speech Attack 4.0 … 50.0 ms, Off [2.0 only]
--- Bx Center Attack 4.0 … 50.0 ms, Off [surround only]
--- Bx Limiter Attack 0 … 100%
--- Bx Delta Release –6 … 6
--- Bx Compression Ratio 1:1 … ∞:1
--- Bx Knee 0 … 50 dB
--- Bx Break 1 … 50 dB
--- Bx Main>Center Max +Delta GR 0…24 dB, Off
--- Bx Main>Center Max –Delta GR 0…24 dB, Off
--- Transient Enhance 0 … 10 ms
Table 3-9: MB Attack/Release Controls